The present invention relates to method and apparatus for fusing cells to produce a variety of cell hybrids, and more particularly to such method and apparatus for use in hybridoma production with a high fusion-and-survival efficiency.
The conventional procedure for producing monoclonal antibodies, i.e., hybridomas, involves several steps. One critical step consists of fusing centrifuge-pelleted myeloma cells with selected cells (e.g., spleen cells) taken from a donor (e.g., immunized mouse). The two cell populations (suspensions) are gradually mixed together and fused using polyethylene glycol (PEG) of molecular weight 1500 Daltons in dropwise fashion at 50% by volume concentration in buffered solution. This adding and mixing continues for about one minute, and is then terminated by adding tissue culture media to stop the PEG-induced toxicity to the cells. The cells are then spun down, the toxic medium (PEG) is removed, and fresh non-toxic medium is added. The cells are then resuspended, and the yield of fused cells is determined by examination under a microscope. The cells are then plated in ninety-six well plates, with the aim of achieving one fused cell per well. A discriminatory medium is applied to the well plates. In this medium the myeloma X spleen fused cell hybrids will thrive, while other cells will either die or not grow during a short period.
Using this standard methodology, generally only 2-3% of the initial cell population are rendered fused, and only a few of these hybrid cells will survive and yield a monoclonal culture. Thus the "fusion-and-survival" efficiency is generally less than 3% and can be as low as 0.001%.
Accordingly, it is an object of the present invention to provide a method and apparatus for fusing cells to produce a variety of cell hybrids.
Another object is to provide such a method and apparatus for hybridoma production.
A further object is to provide such a method and apparatus which has a fusion-and-survival efficiency of at least 40%.